Peelable seal package



Nov. 16, 1965 R. L. LEE 3,217,871

PEELABLE SEAL PACKAGE Filed May 6, 1963 IHIIIIHL HIHHHHI IHHHII!IHIIIINVENTOR. #08597 L. LEE

ATTORNEY 1 United States Patent O 3,217,871 PEELABLE SEAL PACKAGE RobertL. Lee, Norwalk, Conn, assignor to Acme Backing Corporation, Stamford,Conn., a corporation of New York Filed May 6, 1963, Ser. No. 278,374 9Claims. (Cl. 206-632) This invention relates to seal packages forsterilized or non-sterilized contents, and more particularly, concernspackages which are opened by peeling apart sections thereof to exposeand render accessible the contents thereof.

Packages of the envelope type for carrying sterilized objects ormaterials, such as surgical instruments, dressings or the like have beenproposed. Such packages are in the form of sheets or webs of appropriatesize and configuration for enclosing the desired object or material,which sheets are sealed about the peripheral portions thereof. Thesealing material is in the form of resin coatings which lends itself topackage sealing operations by means of heated dies, rollers or bars.

With known packages of the rupturable and peelable seal type, it hasbeen found that the seal has adherency values of opposite extremes. Onthe one hand, the seal may have high adherency values which areeffective when the package is in storage, being transferred orotherwise, prior to opening the same. However, the high adherency valuestend to resist rupture when the package sections are to be peeled apart,making the package opening operation somewhat difiicult.

On the other hand, the seal may have low adherency values, whichfacilitates the peeling operation but provides a relatively low gradeseal which may not be acceptable for most packaging operations. In theformer case, the tendency to resist peeling, materially reduces theutility of the package, particularly when the package carries sterilizeditems such as surgical devices, dressings or the like which have to beaccessible quickly when needed.

Accordingly, an object of this invention is to provide an improvedenvelope package having a peripheral seal structure which provides arelatively tight seal for the envelope sections which is highlyresistant to delamination by forces applied substantially in the planeof the sealed areas, yet lends itself to rupture readily when theenvelope sections are peeled apart by forces applied at right angles tothe plane of the sealed areas, thus making the contents of such apackage readily accessible when needed with minimal manipulativeprocedures for delaminating the envelope sections.

A further object of this invention is to provide an improved peelablepackage made up of opposed sheet sections carrying selectedthermoresponsive coatings; such Coatings allowing the sheet sections tobe hot sealed about the periphery thereof to securely adhere to thesections together, yet being adapted to allow ready delamination uponpeeling the sections away from each other.

Still another object of this invention is to provide an improvedpeelable package wherein the sections thereof are secured together byselected coatings applied to the respective sections, which coatings arecorrelated as to kind and structure as to provide a highly adherent sealresistant to ordinary delaminating forces yet readily rupturable inresponse to a peeling action invoking forces at right angles to theplane of the seal areas.

Other objects of this invention will in part be obvious and in parthereinafter pointed out.

In the drawing, FIG. 1 is a top plan view of a package embodying theinvention, with parts broken away;

FIG. 2 is a partial, enlarged plan View of one of the package sectionsshowing one element of the seal coating;

FIG. 3 is a partial, enlarged plan view of the other of the packagesections showing another element of the seal coating;

FIG. 4 is an enlarged, transverse sectional view showing the opposedpackage sections before sealing;

FIG. 5 is a sectional view similar to that of FIG. 4, showing thepackage sections sealed to each other;

FIG. 6 is a sectional view similar to that of FIG. 4, showing anotherembodiment of the invention;

FIG. 7 is a plan view of one of the package sections of a packageshowing another embodiment of the invention;

FIG. 8 is a plan view of the other of the package sections to beregistered with the section shown in FIG. 7;

FIG. 9 is a partial plan view of a package showing another form of theinvention; and

FIG. 10 is a sectional view taken on the line 10-10 of FIG. 9.

Packages of the peelable seal type are usually in envelope form, beingmade of opposed webs or sheets of paper, foil, film or the like, inaccordance with the object to be enclosed and the condition of sterilityor nonsterility thereof.

In accordance with the instant invention, pairs of webs or sheets to beconverted into packages, are respectively coated on one surface thereofwith selected sealing materials which include thermoplastic resins orother suitable sealants. The coatings may extend over the entire surfaceof the sheets or webs, or may be restricted to the ultimate peripheralseal areas for each package, as by applying the coatings with patterneddies or rollers which are effective to imprint the coating only in thedesired seal areas.

Thus, one of the pair of sheets which are to be opposed to form thepackage, is coated with one resin while the other of the pair of sheetsis coated with another resin. The two resins are selected so that whileeach will tightly adhere to the respective sheets carrying the same, and

the resin coating on one sheet will be adherent to the surface of theother sheet under sealing conditions; the two resins are non-adherent toeach other at all times and' under sealing conditions.

ture under normal conditions, yet the seal is readily ruptured when thesections are peeled apart. Such a seal is obtained when at least one ofthe coatings on the paired 1 sheets is discontinuous so as to expose alarge number of spaced areas of the one sheet surface carrying thecoating.

Thus, when the sheets are sealed together, they are, adhered together atinterrputed intervals where portions of the coating on the other sheetextend through the openings in the discontinuous coating on the onesheet to bond to the exposed surface areas of the one sheet.

As shown in FIG. 1, 10 designates a package embodying the invention. Thesame comprises a pair of opposed sheets of similar size and outline,which enclose an object 13 to be packaged, the sheets being indicated at11 and 12 respectively. Object 13 may be of the type which is to bepackaged under sterile conditions, as for example, a surgeons scalpel,surgical dressing, or the like. understood that object 13 may bepackaged in non-sterile form when the character thereof so dictates.

The sheets 11, 12 are sealed together about the peripheral marginsthereof, as in a seal area 14 of limited width The seal area is but ofcontinuous peripheral extent. located beyond the edges of object 13. Thesheets 11, 12

after described in detail. The sheets 11, .12 are sealed Patented Nov.16, 1965 3 together as an incident to the packaging operation, byappropriate heated dies, rollers or bars which register with orotherwise delineate the seal area 14.

Preferably, portions of sheets 11, 12 at one end thereof are leftunsealed to provide tabs 15, 16 which are to be grasped and displacedaway from each other in directions at right angles to the plane of theseal area 14, to effect a peeling action, thereby progressively openingthe package to expose object 13 for ready removal therefrom.

The sheet 11 has imprinted on one surface thereof a coating 17 of aselected thermoresponsive material which is not only adherent to sheet11, but is also adherent to sheet 12. As shown in FIG. 2, coating 17 iscontinuous throughout its peripheral extent as well as its width.Coating 17 is applied to sheet 11 by an appropriate coating die orroller to provide the desired peripheral configuration which may includethe usual chevron shaped end portion disposed at the tab end of thesheet.

' Sheet 12 has imprinted on one surface thereof a coating 18 of amaterial different from that of coating 17; coating 18 beingcomplementary in outline to coating 17 so that the coatings may beregistered when sheets 11, 12 are in superposed, registered relation.Coating 18 is of a discontinuous character, having spaced openings 19therein which correspondingly provide spaced exposed surface portions 20on sheet 12. Discontinuous coating 18 is produced by an appropriatecoating die which may be of the rotogravure type, with high and lowportions. While one pattern of application of coating 18 to sheet 12 isshown in FIG. 3, it is understood that such coating may take otherpattern forms.

The size and particular disposition of the exposed surface portions 20on sheet 12 may be varied in accordance with the nature of sheet 12, theadherency of coating 17 to sheet 12, and the desired balance ofadherency and rupturability as between sheets 11, 12.

When sheets 11, 12 are properly registered with object 13 therebetween,as an incident to the usual packaging operation, the peripheral coatings17, 18 on the respective sheets will also be in opposed, registeredrelation. As the sealing operation takes place by means of the usualheated dies, rollers or bars, the thermoresponsive material of coating17 will flow through the openings 19 in coating 18 to adhere to theexposed surface areas 20 on sheet 12, thereby bonding sheets 11, 12interruptedly within the seal area 14. However, the openings 19 incoating 18 may be of such a size, configuration and spacing as toprovide an adequate bond between sheets 11, 12.

The materials from Which coatings 17, 18 are derived, are selected sothat they are nonadherent to each other when in contacting relation,during the sealing operation as well as thereafter and over a relativelywide range of temperatures. Thus, as shown in FIG. 5, the surfaceportions 21 of coating 17 which are in contact with surface portions 22of coating 18, after the sealing operation is completed, remain innon-adherent relation after the package has been completed.

Accordingly, when package 10 is to be opened to expose object 13, tabs15, 16 may be grasped and pulled away from each other to effect apeeling action which separates sheets 11, 12 from each other. Theinterrupted adhesion of the sheets 11, 12 in the seal area 14, togetherwith the non-adherent contacting areas of coatings 17 18 facilitate thedelaminating action produced by rupturing forces applied at right anglesto the plane of the seal area 14.

Alternatively, as shown in FIG. 6, the coating 17 on sheet 11 may alsobe of a discontinuous character, like coating 18 on sheet 12. However,the areas 23 of coating 17 must overlap the edges of areas 24 of coating18' and coating areas 23 will flow during the sealing operation throughopenings 25 in coating 18 to adhere to the spaced surface areas 26 onsheet 12.

In the seal shown in FIG. 6, it is preferable that coating 18' on Sheetll be elect d 50 that it is non-adherent to the sheet 11 on the exposedsurface areas thereof as at 27. The overlap of the coating areas 23, 24may be produced by proper imprint of the respective coatings 17 and 18on sheets 11, 12 and the desired registry thereof.

By way of example, a package 10 was formed wherein sheet 11 wascellophane and sheet 12 was paper. Sheet 11 was imprinted on one sidethereof with a coating 17 of a low density polyethylene resin, the samebeing continuous throughoutthe seal area 14. Sheet 12 was imprinted onside thereof with a discontinuous coating 18 derived from a mixture ofequal parts A2 second nitrocellulose and polyvinyl acetate admixed witha plasticizer of methyl phthalyl ethyl glycolate and a solvent ofisopropyl acetate and toluene, all by weight.

The package 10 was formed on conventional packaging machinery, withobject 13 suitably interposed between sheets 11, 12 and the seal 14being formed by dies of suitable outline at a sealing temperature ofabout 325 F. The resultant package was resistant to delamination untiltabs 15, 16 were pulled in opposite directions and at right angles tothe plane of seal area 14.

It is understood that the sheets 11, 12 forming package 10, may bederived from various webs including paper, cellophane, plastic filmssuch as Mylar or the like, metal foils including aluminum foil, andfabrics in woven or nonwoven form. The sheets 11, 12 are paired inaccordance with the specifications of the package to be formed. Thecoatings 17, 18 or 17', 18 are paired from materials which arenon-adherent while in contact either at sealing temperatures ortemperatures to be encountered by the package in use. Preferably, onlyone of the pair of coatings is adherent to the surface of the sheetopposed thereto.

Thus, a continuous coating of polypropylene may be paired with adiscontinuous coating of a vinyl copolymer; polyethylene paired withcellulose acetate; and a low melting point polyethylene paired with ahigh melting point polypropylene. Also, the same type of resin may beused in paired combinations wherein the respective components of thepair are of different degrees of polymerization, density, melting pointor other characteristic which leaves the pair of resins in non-adherentrelation although in contact, over a wide range of temperatures.

In addition to polyethylene and polypropylene, the continuous coating 17or coating 17 may be derived from polyvinyl acetate-chloride copolynieror polyvinylidene chloride.

Typical formulations for the discontinuous coatings 18 or 18 include:(a) polyvinyl acetate-chloride copolymer 17.5%, mixed fatty amides 7.5%,and methyl ethyl ketone 75%; (b) polyvinyl acetate-chloride copolymer(VYNS) 15.0%, polyvinyl acetate-chloride copolymer (VYHH) 8.75%, mixedfatty amides 1.25% and 2-nitropropane 75.00%; (c) 18/25 cps. RSnitrocellulose 24.0%, polymethyl acrylate 8.0%, zinc stearate 3.0%,methyl ethyl ketone, 50.0% and isopropyl alcohol 15.0%; (d) cyclizedrubber (Pliolite S-7) 10.0%, paraflin wax 6.0%, dimerized resin acids(Dymerex) 4.0% and toluene 80.0%; (e) cellulose acetate butyrate 9.80%,urea formaldehyde resin 16.30%, sucrose ester 11.30%, polymethyl styrene6.40%, epoxy resin (Epon 836) 4.00%, silicone oil 0.05%,p-toluenesulfonic acid/n-butanol (50:50) 0.65%, toluene 24.30%; ethylalcohol 16.70% and isobutyl alcohol 10.50%. All proportions in theforegoing formulations being by weight.

In addition to the formulations noted above, the coatings 18 or 18 mayalso be derived from starch; casein; a mixture of kaolin clay andcasein; sodium silicate or bone glue. It will be apparent that in someinstances, the paired coatings may be in interchanged relation. Thus,the polyethylene or polypropylene used for coatings 17 or 17 may bereplaced by selected formulations from (a) to (e) set forth above, inwhich case the coatings 18 or 18' are selected accordingly to providethe com binations described above.

en it will thus be apparent that when sheets 11, 12 have been selectedfor the object 13 to be packaged, the appropriate coatings applicable tothe seal areas of the sheets are selected so that they are 1)non-adherent though in contact over a wide range of temperaturesincluding the sealing temperature; (2) one coating is adherent to thesurface portions of the sheet opposed to the sheet carrying the onecoating; and (3) the other coating is nonadherent to the sheet opposedto the sheet carrying the other coating.

The exposed surface areas 20 on sheet 12 within the seal area 14 mayamount to about 50% of the total area of said seal area 14. However,such exposed surface area may range from about 25% to about 75% inaccordance with the desired balance of adherency and peelability of theresultant seal.

While the seal coatings 17, 18 are shown as being limited to the sealarea 14 on the respective sheets 11, 12 and defined by an appropriatesealing die, rollers or bar; it is understood that such coatings may beapplied uniformly over the entire surface of the respective sheets 11,12 or the Webs from which such sheets are derived. In such case, thecoated sheets paired as described above may be used in making packageshaving varied seal area configurations and of varied transversedimension. Thus, the peripheral seal area 14 may be completelyrectangular in configuration, rather then having a chevron portion atone end thereof, as shown in FIG. 1; or the frame portion enclosed byseal area 14 may be varied in extent to accord with the extent of theparticular object 13 being packaged.

The sheets 11, 12 may be in the form of continuous webs of selectedpaired materials with repeat imprints thereon of coatings 17, 18respectively; the same being arranged in side by side or end to endrelation. Such continuous webs may then be fed into packaging machines,not shown, wherein the objects 13 are properly located between the websand within the respective seal areas. Appropriate heat sealing dies,rollers or bars are then operative to produce packages in a continuousor semi-continuous manner.

To facilitate the seaming operations, particularly when using heatedrollers to form transverse seams in packages 10; the seam coatings maybe applied to the opposed sheets 11, 12 as shown in FIG. 7.

Sheet 12 carries coating 18 in repeated, adjacent patterns inrectangular frame form, representing multiple package sections. Eachframe comprises side areas 30, 31 and end areas 32, 33. The coating inareas 30, 31 and 32 are of a discontinuous character to provide spaced,exposed surface areas in the seal area of sheet 12, as previouslydescribed. End area 33 comprises an inner transverse end portion 34which is of a discontinuous character, similar to that of areas 30-32,and an outer transverse end portion 35 wherein the coating is of acontinuous character. The coating die used to apply the coating material18 is formed accordingly to deposit the discontinuous and continuouscoating portions corresponding to the several frame areas 3035.

The opposed sheet 11 carries coating 17, in repeated, adjacent patternsin rectangular frame form for registry with the patterns on sheet 12.Each frame on sheet 11 comprises side areas 36, 37 and end areas 38, 39,with the coating thereof being continuous in character as pre viouslydescribed in connection with the showing in FIG. 2. End area 39 has awidth equal to the combined width of area portions 34, 35 on sheet 12.

It will be apparent that when sheets 11, 12 pass through the usualpackaging machinery, sealing of the opposite ends of the packages 10 maybe performed by heated rollers contacting said sheets in the areas 34,35; 39, as well as 38. Thus, end areas 32, 38 are sealed together at oneend of the package, while at the other end thereof, area 34 of sheet 12is sealed to the inner portion of area 39 on sheet 11. This leaves area35 on sheet 12 in nonsealed relation to the outer portion of area 39 onsheet 11,

to thereby provide tab portions for peeling the package sections apartto expose the packaged object 13. The multiple patterns imprinted onsheets 11, 12 representing adjacent packages may be separably defined byperforation lines as at 40, formed during the packaging operations, in amanner known in the art.

While the discontinuous coatings 18, 18 are shown as being applied toone of the sheets forming the package having a peelable seal; it isunderstood that such coatings 18, 18' may be directly coated orimprinted on the continuous coatings 17, 17' in proper position for theheat sealing operation.

In another embodiment of the invention, shown in FIGS. 9, 10; a peelableseal is formed between opposed package sheet sections 50, 51 in a sealarea 14 of selected geometrical outline. Each sheet section 50, 51 isprecoated on one side throughout the surface thereof with athermoplastic resin layer such as polyethylene to provide opposedcoatings 52, 53 when said sheet sections are in opposed relation; suchcoatings 52, 53 being continuous throughout their extent.

A coating 54 of silicone (organochlorosilanes) is imprinted on one ofthe coatings 52, 53 in the seal area 14. Coating 54 is discontinuous soas to provide closely spaced openings or spaces. Upon heat sealing thesheet sections 50, 51 together in seal area 14, the coatings 52, 53 willfuse together through the openings or spaces in coating 54.

Since the coating 54 is non-adherent to coatings 52, 53, the bondbetween sheets 50, 51 in seal area 14 will be interrupted at intervalscorresponding to the portions of said coatings 52, 53 in contact withcoating 54, thusproviding a peelable seal whereby the package is readilyopened when the tab portions thereof are pulled in opposite directions.

The sheets forming the package of the instant invention and the severalcoatings thereon, may be selected to allow for sterilization of thepackage contents after the packaging operation, by means of ethylene orpropylene oxide, in a manner known in the art.

As various changes might be made in the embodiments of the disclosedinvention without departing from the spirit thereof, it is understoodthat all matter herein described or shown shall be deemed illustrativeand not limiting except as set forth in the appended claims.

What is claimed is:

1. A package for an object comprising a pair of opposed sheets forenclosing the object therebetween with peripheral portions of saidsheets extending beyond the edges of said object, and bonding means forsecuring the opposed marginal portions of said sheets about theperiphery thereof, said bonding means comprising a pair of opposedthermoresponsive coatings applied to at least the marginal portions ofthe respective, sheets, atleast one of said coatings being discontinuousto expose closely spaced small surface portions of the sheet bearingsaid one coating, the coating on the other of said sheets 11E?- ingspaced portions thereof adherent to the exposed surface portions of saidfirst mentioned sheet, the opposed contacting portions of said coatingsbeing in nomadherent relation to each other over a wide range oftemperatures the spacing of the adherent areas of said sheets providinga seal resistant to delamination by forces applied in the plane of theseal areas yet permitting said sheets to be delaminated andprogressively separated from each other to expose the enclosed objectupon displacing opposed portions of said sheets away from each other andpeeling said displaced sheet portions away from each other and indirections at right angles to the plane of the bonded sheet portions.

2. A package for an object comprising a pair of opposed sheets forenclosing the object therebetween with peripheral portions of saidsheets extending beyond the edges of said object to provide opposedmarginal sheet portions, a coating of thermoplastic material on theinner surface of each of said sheets at said opposed marginal portionsthereof, one of said coatings being discontinuous to provide a largenumber of closely spaced surface portions on the one sheet carrying saidone coating, the other coating on the other sheet having a plurality ofspaced portions thereof in sealed relation to the exposed surfaceportions on said one sheet and a plurality of spaced portions thereof incontacting relation to opposed portions of the one coating on said onesheet, the contacting portions of the coatings on said sheets being innon-adherent relation whereby said sheets are sealed together at theperipheral margin portions thereof discontinuously to form a bondtherebetween which is resistant to delamination but Which is rupturedupon pulling opposed marginal sheet portions away from each other indirections at right angles to the plane of the sealed areas thereof.

3. A sealed package for enclosing an object comprising a pair of sheetsin opposed relation with said object therebetween, said sheets havingopposed peripheral marginal portions extending beyond the edges of saidobject, means for sealing the marginal portions of said sheets to eachother around the periphery of the enclosed object, said sealing meanscomprising a first thermoplastic resin layer on the inner surface of oneof said sheets on at least the peripheral marginal portion thereof and asecond thermoplastic resin layer on the inner surface of the other ofsaid sheets and in opposed relation to said first resin layer, one ofsaid resin layers being discontinuous to expose a large number ofclosely spaced small surface portions. of the sheet carrying said oneresin layer, the other of said resin layers having a large number ofclosely spaced portions in heat sealed relation to the exposed surfaceportions of said one sheet and a plurality of spaced portions in contactwith opposed portions of said one resin layer, said contacting resinportions being non-adherent to each other at sealing temperatures,whereby said sheets are sealed to each other at the peripheral portionsthereof, said seal being rupturable upon pulling opposed marginalportions of said sheets away from each other.

4. A sealed package for an object comprising a pair of opposed sheetsfor enclosing the object and having peripheral marginal portionsextending beyond the edges of the enclosed object to dispose saidperipheral marginal sheet portions in opposed relation, a peripheralseal be tween said opposed marginal sheet portions, said seal comprisinga first thermoresponsive coating adherent to the inner surface of one ofsaid sheets at the marginal portions thereof and a secondthermoresponsive coating adherent to the inner surface of the other ofsaid sheets and in opposed relation to said first coating, said coatingshaving spaced contacting portions in non-adherent relation over a widerange of extreme temperatures, one of said coatings being discontinuousto expose a large number of closely spaced small surface portions alongthe entire periphery of the one sheet carrying said one coating, theother of said coatings including a large number of closely spacedportions in sealed, adherent relation to the exposed surface portions ofsaid one sheet, said exposed surface portions on said one sheet beingsufficiently close to each other to provide a seal between said sheetswhich offers substantial resistance to rupture by forces appliedsubstantially within the plane of the seal yet being rupturable uponapplication of delaminating forces substantially at right angles to theplane of the seal and in opposite directions.

5. A sealed package as in claim 4 wherein the exposed surface portions011 said one sheet constitute from about 25% to about 75% of the totalarea of said one coating on said one sheet.

6. A sealed package as in claim 4 wherein the exposed surface portionson said one sheet constitute about 50% of the total area of said onecoating on said one sheet.

7. A sealed package as in claim 4 wherein the other of said coatings isdiscontinuous to expose surface portions of the sheet carrying saidother coating, the spaced coating portions on the respective sheetsbeing in displaced, overlapping relation to each other, the spacedportions of said other coating being in sealed adherent relation to theexposed surface portions of said one sheet, and the spaced portions ofsaid one coating on said one sheet being in contacting, non-adherentrelation to the exposed surface portions of said other sheet.

8. A sealed package for contents thereof comprising a pair of sheetswith the contents therebetween, the edges of said sheets overlapping andextending beyond the edges of the contents, thereby providing edgeportions of said sheets around the edges of the contents, each of saidsheets in said edge portions thereof having a thermoplastic resincoating on the inner surface thereof, one of said coatings beingdiscontinuous to provide a large number of closely spaced small exposedsurface portions on the one sheet carrying said one coating, the otherof said coatings on the other sheet having spaced surface portionsthereof extending through the discontinuities in said one coating and inthermally bonded relation to the exposed surface portions of said onesheet, said other coating further including spaced portions thereof incontacting relation to opposed portions of said one coating, thecontacting portions of said coatings being in nonadherent relation toeach other over a wide range of extreme temperatures.

9. A sealed package as in claim 8 wherein said one sheet includes at oneend thereof a transversely extending inner coating portion which isdiscontinuous to provide a plurality of spaced exposed surface portionsof said one sheet and a transversely extending outer coating portionextending to the outer edge at said one end of the one sheet, said outercoating portion being continuous, the other sheet including at one endthereof a continuous coating portion in opposed relation to the innerand outer coating portions on said one sheet, said last mentionedcontinuous coating portion including an inner portion having spacedportions extending through the discontinuities in the opposed innercoating portion on said one sheet and in adherent relation to the spacedexposed surface portions of said one sheet, said last mentionedcontinuous coating portion further including an outer portion inopposed, non-adherent relation to the opposed outer coating portion onsaid one sheet whereby to provide separable sheet portions in saidsheets at said one end thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,071,921 2/1937Dickson 16l-1 14 2,122,480 '7/1938 Lowey.

2,133,946 10/1938 Bloomer 2295l 2,330,666 9/1943 Berkowitz.

2,676,702 4/1954 Whitefoot.

2,715,089 8/1955 Michener et al 156-289 2,745,592 5/1956 Steck 229-512,810,507 10/1957 Saunders 22937 2,954,116 9/1960 Maso et al. 206-63.2 X2,998,880 9/1961 Ladd 206-632 3,001,689 9/1961 Burton.

JOSEll-I R. LECLAIR, Primary Examiner.

FRANKLIN T. GARRETT, Examiner.

1. A PACKAGE FOR AN OBJECT COMPRISING A PAIR OF OPPOSED SHEETS FORENCLOSING THE OBJECT THEREBETWEEN WITH PERIPHERAL PORTIONS OF SAIDSHEETS EXTENDING BEYOND THE EDGES OF SAID OBJECT, AND BONDING MEANS FORSECURING THE OPPOSED MARGINAL PORTIONS OF SAID SHEETS ABOUT THEPERIPHERY THEREOF, SAID BONDING MEANS COMPRISING A PAIR OF OPPOSEDTHERMORESPONISIVE COATINGS APPLIED TO AT LEAST THE MARGINAL PORTIONS OFTHE RESPECTIVE SHEETS, AT LEAST ONE OF SAID COATINGS BEING DISCONTINUOUSTO EXPOSE CLOSELY SPACED SMALL SURFACE PORTIONS OF THE SHEET BEARINGSAID ONE COATING, THE COATING ON THE OTHER OF SAID SHEETS HAVING SPACEDPORTIONS THEREOF ADHERENT TO THE EXPOSED SURFACE PORTIONS OF SAID FIRSTMENTIONED SHEET, THE OPPOSED CONTACTING PORTIONS OF SAID COATINGS BEINGIN NON-ADHERENT RELATION TO EACH OTHER OVER A WIDE RANGE OF TEMPERATURESTHE SPACING OF THE ADHERENT AREAS OF SAID SHEETS PROVIDING A SEALRESISTANT TO DELAMINATION BY FORCES APPLIED IN THE PLANE OF THE SEALAREAS YET PERMITTING SAID SHEETS TO BE DELAMINATED AND PROGRESSIVELYSEPARATED FROM EACH OTHER TO EXPOSE THE ENCLOSED OBJECT UPON DISPLACINGOPPOSED PORTIONS OF SAID SHEETS AWAY FROM EACH OTHER AND PEELING SAIDDISPLACED SHEET PORTIONS AWAY FROM EACH OTHER AND IN DIRECTIONS AT RIGHTANGLES TO THE PLANE OF THE BONDED SHEET PORTIONS.